#pragma once
namespace feather::md5 {
#include <string.h>

	typedef unsigned char md5_byte_t; /* 8-bit byte */
	typedef unsigned int md5_word_t; /* 32-bit word */

									 /* Define the state of the MD5 Algorithm. */
	typedef struct md5_state_s {
		md5_word_t count[2];	/* message length in bits, lsw first */
		md5_word_t abcd[4];		/* digest buffer */
		md5_byte_t buf[64];		/* accumulate block */
	} md5_state_t;

#undef BYTE_ORDER	/* 1 = big-endian, -1 = little-endian, 0 = unknown */
#ifdef ARCH_IS_BIG_ENDIAN
#  define BYTE_ORDER (ARCH_IS_BIG_ENDIAN ? 1 : -1)
#else
#  define BYTE_ORDER 0
#endif

#define T_MASK ((md5_word_t)~0)
#define T1 /* 0xd76aa478 */ (T_MASK ^ 0x28955b87)
#define T2 /* 0xe8c7b756 */ (T_MASK ^ 0x173848a9)
#define T3    0x242070db
#define T4 /* 0xc1bdceee */ (T_MASK ^ 0x3e423111)
#define T5 /* 0xf57c0faf */ (T_MASK ^ 0x0a83f050)
#define T6    0x4787c62a
#define T7 /* 0xa8304613 */ (T_MASK ^ 0x57cfb9ec)
#define T8 /* 0xfd469501 */ (T_MASK ^ 0x02b96afe)
#define T9    0x698098d8
#define T10 /* 0x8b44f7af */ (T_MASK ^ 0x74bb0850)
#define T11 /* 0xffff5bb1 */ (T_MASK ^ 0x0000a44e)
#define T12 /* 0x895cd7be */ (T_MASK ^ 0x76a32841)
#define T13    0x6b901122
#define T14 /* 0xfd987193 */ (T_MASK ^ 0x02678e6c)
#define T15 /* 0xa679438e */ (T_MASK ^ 0x5986bc71)
#define T16    0x49b40821
#define T17 /* 0xf61e2562 */ (T_MASK ^ 0x09e1da9d)
#define T18 /* 0xc040b340 */ (T_MASK ^ 0x3fbf4cbf)
#define T19    0x265e5a51
#define T20 /* 0xe9b6c7aa */ (T_MASK ^ 0x16493855)
#define T21 /* 0xd62f105d */ (T_MASK ^ 0x29d0efa2)
#define T22    0x02441453
#define T23 /* 0xd8a1e681 */ (T_MASK ^ 0x275e197e)
#define T24 /* 0xe7d3fbc8 */ (T_MASK ^ 0x182c0437)
#define T25    0x21e1cde6
#define T26 /* 0xc33707d6 */ (T_MASK ^ 0x3cc8f829)
#define T27 /* 0xf4d50d87 */ (T_MASK ^ 0x0b2af278)
#define T28    0x455a14ed
#define T29 /* 0xa9e3e905 */ (T_MASK ^ 0x561c16fa)
#define T30 /* 0xfcefa3f8 */ (T_MASK ^ 0x03105c07)
#define T31    0x676f02d9
#define T32 /* 0x8d2a4c8a */ (T_MASK ^ 0x72d5b375)
#define T33 /* 0xfffa3942 */ (T_MASK ^ 0x0005c6bd)
#define T34 /* 0x8771f681 */ (T_MASK ^ 0x788e097e)
#define T35    0x6d9d6122
#define T36 /* 0xfde5380c */ (T_MASK ^ 0x021ac7f3)
#define T37 /* 0xa4beea44 */ (T_MASK ^ 0x5b4115bb)
#define T38    0x4bdecfa9
#define T39 /* 0xf6bb4b60 */ (T_MASK ^ 0x0944b49f)
#define T40 /* 0xbebfbc70 */ (T_MASK ^ 0x4140438f)
#define T41    0x289b7ec6
#define T42 /* 0xeaa127fa */ (T_MASK ^ 0x155ed805)
#define T43 /* 0xd4ef3085 */ (T_MASK ^ 0x2b10cf7a)
#define T44    0x04881d05
#define T45 /* 0xd9d4d039 */ (T_MASK ^ 0x262b2fc6)
#define T46 /* 0xe6db99e5 */ (T_MASK ^ 0x1924661a)
#define T47    0x1fa27cf8
#define T48 /* 0xc4ac5665 */ (T_MASK ^ 0x3b53a99a)
#define T49 /* 0xf4292244 */ (T_MASK ^ 0x0bd6ddbb)
#define T50    0x432aff97
#define T51 /* 0xab9423a7 */ (T_MASK ^ 0x546bdc58)
#define T52 /* 0xfc93a039 */ (T_MASK ^ 0x036c5fc6)
#define T53    0x655b59c3
#define T54 /* 0x8f0ccc92 */ (T_MASK ^ 0x70f3336d)
#define T55 /* 0xffeff47d */ (T_MASK ^ 0x00100b82)
#define T56 /* 0x85845dd1 */ (T_MASK ^ 0x7a7ba22e)
#define T57    0x6fa87e4f
#define T58 /* 0xfe2ce6e0 */ (T_MASK ^ 0x01d3191f)
#define T59 /* 0xa3014314 */ (T_MASK ^ 0x5cfebceb)
#define T60    0x4e0811a1
#define T61 /* 0xf7537e82 */ (T_MASK ^ 0x08ac817d)
#define T62 /* 0xbd3af235 */ (T_MASK ^ 0x42c50dca)
#define T63    0x2ad7d2bb
#define T64 /* 0xeb86d391 */ (T_MASK ^ 0x14792c6e)


	static void
		md5_process(md5_state_t *pms, const md5_byte_t *data /*[64]*/)
	{
		md5_word_t
			a = pms->abcd[0], b = pms->abcd[1],
			c = pms->abcd[2], d = pms->abcd[3];
		md5_word_t t;
#if BYTE_ORDER > 0
		/* Define storage only for big-endian CPUs. */
		md5_word_t X[16];
#else
		/* Define storage for little-endian or both types of CPUs. */
		md5_word_t xbuf[16];
		const md5_word_t *X;
#endif

		{
#if BYTE_ORDER == 0
			/*
			* Determine dynamically whether this is a big-endian or
			* little-endian machine, since we can use a more efficient
			* algorithm on the latter.
			*/
			static const int w = 1;

			if (*((const md5_byte_t *)&w)) /* dynamic little-endian */
#endif
#if BYTE_ORDER <= 0		/* little-endian */
			{
				/*
				* On little-endian machines, we can process properly aligned
				* data without copying it.
				*/
				if (!((data - (const md5_byte_t *)0) & 3)) {
					/* data are properly aligned */
					X = (const md5_word_t *)data;
				}
				else {
					/* not aligned */
					memcpy(xbuf, data, 64);
					X = xbuf;
				}
			}
#endif
#if BYTE_ORDER == 0
			else			/* dynamic big-endian */
#endif
#if BYTE_ORDER >= 0		/* big-endian */
			{
				/*
				* On big-endian machines, we must arrange the bytes in the
				* right order.
				*/
				const md5_byte_t *xp = data;
				int i;

#  if BYTE_ORDER == 0
				X = xbuf;		/* (dynamic only) */
#  else
#    define xbuf X		/* (static only) */
#  endif
				for (i = 0; i < 16; ++i, xp += 4)
					xbuf[i] = xp[0] + (xp[1] << 8) + (xp[2] << 16) + (xp[3] << 24);
			}
#endif
		}

#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))

		/* Round 1. */
		/* Let [abcd k s i] denote the operation
		a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
#define F(x, y, z) (((x) & (y)) | (~(x) & (z)))
#define SET(a, b, c, d, k, s, Ti)\
  t = a + F(b,c,d) + X[k] + Ti;\
  a = ROTATE_LEFT(t, s) + b
		/* Do the following 16 operations. */
		SET(a, b, c, d, 0, 7, T1);
		SET(d, a, b, c, 1, 12, T2);
		SET(c, d, a, b, 2, 17, T3);
		SET(b, c, d, a, 3, 22, T4);
		SET(a, b, c, d, 4, 7, T5);
		SET(d, a, b, c, 5, 12, T6);
		SET(c, d, a, b, 6, 17, T7);
		SET(b, c, d, a, 7, 22, T8);
		SET(a, b, c, d, 8, 7, T9);
		SET(d, a, b, c, 9, 12, T10);
		SET(c, d, a, b, 10, 17, T11);
		SET(b, c, d, a, 11, 22, T12);
		SET(a, b, c, d, 12, 7, T13);
		SET(d, a, b, c, 13, 12, T14);
		SET(c, d, a, b, 14, 17, T15);
		SET(b, c, d, a, 15, 22, T16);
#undef SET

		/* Round 2. */
		/* Let [abcd k s i] denote the operation
		a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
#define G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
#define SET(a, b, c, d, k, s, Ti)\
  t = a + G(b,c,d) + X[k] + Ti;\
  a = ROTATE_LEFT(t, s) + b
		/* Do the following 16 operations. */
		SET(a, b, c, d, 1, 5, T17);
		SET(d, a, b, c, 6, 9, T18);
		SET(c, d, a, b, 11, 14, T19);
		SET(b, c, d, a, 0, 20, T20);
		SET(a, b, c, d, 5, 5, T21);
		SET(d, a, b, c, 10, 9, T22);
		SET(c, d, a, b, 15, 14, T23);
		SET(b, c, d, a, 4, 20, T24);
		SET(a, b, c, d, 9, 5, T25);
		SET(d, a, b, c, 14, 9, T26);
		SET(c, d, a, b, 3, 14, T27);
		SET(b, c, d, a, 8, 20, T28);
		SET(a, b, c, d, 13, 5, T29);
		SET(d, a, b, c, 2, 9, T30);
		SET(c, d, a, b, 7, 14, T31);
		SET(b, c, d, a, 12, 20, T32);
#undef SET

		/* Round 3. */
		/* Let [abcd k s t] denote the operation
		a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define SET(a, b, c, d, k, s, Ti)\
  t = a + H(b,c,d) + X[k] + Ti;\
  a = ROTATE_LEFT(t, s) + b
		/* Do the following 16 operations. */
		SET(a, b, c, d, 5, 4, T33);
		SET(d, a, b, c, 8, 11, T34);
		SET(c, d, a, b, 11, 16, T35);
		SET(b, c, d, a, 14, 23, T36);
		SET(a, b, c, d, 1, 4, T37);
		SET(d, a, b, c, 4, 11, T38);
		SET(c, d, a, b, 7, 16, T39);
		SET(b, c, d, a, 10, 23, T40);
		SET(a, b, c, d, 13, 4, T41);
		SET(d, a, b, c, 0, 11, T42);
		SET(c, d, a, b, 3, 16, T43);
		SET(b, c, d, a, 6, 23, T44);
		SET(a, b, c, d, 9, 4, T45);
		SET(d, a, b, c, 12, 11, T46);
		SET(c, d, a, b, 15, 16, T47);
		SET(b, c, d, a, 2, 23, T48);
#undef SET

		/* Round 4. */
		/* Let [abcd k s t] denote the operation
		a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
#define I(x, y, z) ((y) ^ ((x) | ~(z)))
#define SET(a, b, c, d, k, s, Ti)\
  t = a + I(b,c,d) + X[k] + Ti;\
  a = ROTATE_LEFT(t, s) + b
		/* Do the following 16 operations. */
		SET(a, b, c, d, 0, 6, T49);
		SET(d, a, b, c, 7, 10, T50);
		SET(c, d, a, b, 14, 15, T51);
		SET(b, c, d, a, 5, 21, T52);
		SET(a, b, c, d, 12, 6, T53);
		SET(d, a, b, c, 3, 10, T54);
		SET(c, d, a, b, 10, 15, T55);
		SET(b, c, d, a, 1, 21, T56);
		SET(a, b, c, d, 8, 6, T57);
		SET(d, a, b, c, 15, 10, T58);
		SET(c, d, a, b, 6, 15, T59);
		SET(b, c, d, a, 13, 21, T60);
		SET(a, b, c, d, 4, 6, T61);
		SET(d, a, b, c, 11, 10, T62);
		SET(c, d, a, b, 2, 15, T63);
		SET(b, c, d, a, 9, 21, T64);
#undef SET

		/* Then perform the following additions. (That is increment each
		of the four registers by the value it had before this block
		was started.) */
		pms->abcd[0] += a;
		pms->abcd[1] += b;
		pms->abcd[2] += c;
		pms->abcd[3] += d;
	}

	void
		md5_init(md5_state_t *pms)
	{
		pms->count[0] = pms->count[1] = 0;
		pms->abcd[0] = 0x67452301;
		pms->abcd[1] = /*0xefcdab89*/ T_MASK ^ 0x10325476;
		pms->abcd[2] = /*0x98badcfe*/ T_MASK ^ 0x67452301;
		pms->abcd[3] = 0x10325476;
	}

	void
		md5_append(md5_state_t *pms, const md5_byte_t *data, int nbytes)
	{
		const md5_byte_t *p = data;
		int left = nbytes;
		int offset = (pms->count[0] >> 3) & 63;
		md5_word_t nbits = (md5_word_t)(nbytes << 3);

		if (nbytes <= 0)
			return;

		/* Update the message length. */
		pms->count[1] += nbytes >> 29;
		pms->count[0] += nbits;
		if (pms->count[0] < nbits)
			pms->count[1]++;

		/* Process an initial partial block. */
		if (offset) {
			int copy = (offset + nbytes > 64 ? 64 - offset : nbytes);

			memcpy(pms->buf + offset, p, copy);
			if (offset + copy < 64)
				return;
			p += copy;
			left -= copy;
			md5_process(pms, pms->buf);
		}

		/* Process full blocks. */
		for (; left >= 64; p += 64, left -= 64)
			md5_process(pms, p);

		/* Process a final partial block. */
		if (left)
			memcpy(pms->buf, p, left);
	}

	void
		md5_finish(md5_state_t *pms, md5_byte_t digest[16])
	{
		static const md5_byte_t pad[64] = {
			0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
		};
		md5_byte_t data[8];
		int i;

		/* Save the length before padding. */
		for (i = 0; i < 8; ++i)
			data[i] = (md5_byte_t)(pms->count[i >> 2] >> ((i & 3) << 3));
		/* Pad to 56 bytes mod 64. */
		md5_append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
		/* Append the length. */
		md5_append(pms, data, 8);
		for (i = 0; i < 16; ++i)
			digest[i] = (md5_byte_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
	}

	inline std::string md5_hash_string(std::string const & s) {
		char digest[16];

		md5_state_t state;

		md5_init(&state);
		md5_append(&state, (md5_byte_t const *)s.c_str(), s.size());
		md5_finish(&state, (md5_byte_t *)digest);

		std::string ret;
		ret.resize(16);
		std::copy(digest, digest + 16, ret.begin());

		return ret;
	}

	inline std::string md5_string(std::string const & s) {
		using namespace md5;
		unsigned char digest[16];

		md5_state_t state;

		md5_init(&state);
		md5_append(&state, (const unsigned char *)s.c_str(), s.size());
		md5_finish(&state, digest);

		std::string result;
		char buf[32];
		for (int i = 0; i<16; i++) {
			sprintf(buf, "%02x", digest[i]);
			result.append(buf);
		}

		return result;
	}
}